SVG does not achieve clipping by changing the graphics state
(being declarative SVG doesn't have a graphics state as
such). Instead a clipping path has an id, subsequent elements
that are bound by the clipping path are tagged with a
clip-path attribute that references the clipping path id:

clip-path=\"url(#clip1)\"

The operations to build XML elements (e.g. element_path) don't
take more parameters than necessary, and are expected to be
augmented with attributes using add_attr and add_attrs from
the XML.Light library.